KR900002170Y1 - Automatic lighting control circuit - Google Patents

Abstract

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Description

Automatic lighting circuit

1 is a circuit diagram showing an embodiment of the present invention.

2 is a waveform diagram according to FIG. 1.

* Explanation of symbols for main parts of the drawings

1: light detecting unit 2: pulse generating unit

3,6 flip-flop 4: triac driving part

5: overcurrent detector 7: reset signal generator

Cds1, Cds2: Photoconductive element VR1, VR2: Variable resistor

COMP1-CPMP4: Comparator TAC: Triac

LAMP: Bulb TR1: Transistor

OPTO: Optocoupler CT: Current Transformer

The present invention relates to an automatic lighting circuit, and more particularly, to light up a little fast in the dark state and to turn off a little fast in the bright state, and to an automatic light circuit to turn off the light of the bulb when overcurrent flows to the bulb of more than rated .

In general, an auto-lighting circuit uses a photoconductive element (Cds cell) that converts light into an electrical signal, and operates to turn on a light bulb when it is dark at a constant illuminance and to turn off the light bulb when it is bright at that illuminance. However, in the light adaptation relationship of a person, he wants to turn on the light bulb in high light in the dark as in the evening, in low light in the bright like dawn, and turns off the light in low light in the bright light. It is possible to increase the convenience and power of the lighting circuit.

The present invention has been devised in consideration of such a situation. As a comparator, a pulse signal is generated when it becomes dark and light, respectively, and a light bulb is turned on or off at the instant of generating the pulse signal, but at a high illuminance due to the difference in the pulse width of the pulse signal. The object of the present invention is to provide an automatic lighting circuit that is turned on and turned off at low illuminance, and turns off the driving of a bulb when a photocurrent exceeding the rated value is generated.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram illustrating an embodiment of the present invention. The photodetector 1 having a resistor R1 and a photoconductive element Cds1 connected in series outputs a voltage inversely proportional to ambient illumination. High outputs low voltage and low illumination outputs high voltage. These photovoltaic voltages are supplied to the comparators COMP1 and COMP2 of the pulse generator 2, respectively, to the inverting terminal (-) at the comparator COMP1 and the non-inverting terminal (+) at the comparator COMP2. .

On the other hand, the reference terminal regulated by the variable resistor VR2 is supplied to the input terminal to which the optical sensing voltage of the comparator COMP1 and COMP2 is not supplied. The non-inverting terminal of the comparator COMP1 has a higher host voltage. The variable resistors VR1 and VR2 are adjusted such that a voltage is supplied and a reference voltage lower than that of the comparator COMP1 is supplied to the inverting terminal (-) of the comparator COMP2. Then, the comparators COMP1 and COMP2 output the voltages shown in FIGS. That is, the comparator COMP1 operates at a low illuminance but outputs a high level signal during the day and a low level at night, and the comparator COMP2 operates at a high illuminance but outputs a low level signal during the day and a high level at night. . When the output terminals of the two comparators COMP1 and COMP2 that operate in this way are interconnected, the result is a logical multiplication circuit, which outputs a pulse signal as shown in FIG. This pulse signal is generated twice in the evening and at dawn, and the magnitude of the pulse width is determined by adjusting the two reference voltages of the comparators COMP1 and COMP2 with the variable resistors VR1 and VR2.

Here, the resistor R6 is used as a pull-up resistor in which the comparator COMP1 and COMP2 are open collector types, and the capacitor C1 is used to stabilize the output pulse by preventing the unstable operation of the comparator COMP1 and COMP2. .

On the other hand, the non-inverting terminal (+) of the comparator COMP3 is supplied with the host voltage by the resistors R16 and R17, and the reference voltage is set lower than the reference voltage of the comparator COMP2 so that the reference voltage of FIG. Causes the same signal to be output Therefore, during the day, the two flip-flops 3 and 6 are reset by the reset signal generator 7 composed of the comparator COMP3, and at night, the reset is released to the pulse generator 2 while the reset is released. Is operated.

When the flip-flop 3 is reset by the reset signal generator 7 during the day and is supplied in the evening with a pulse signal supplied from the pulse generator 2, the flip-flop 3 is triggered to the output terminal Q. Output a high level signal. Then, the light emitting diode LED is turned on while the transistor TR1 is turned on through the resistors R7 and R8, and the resistance value of the photoconductive device Cds2 is reduced by turning on the light emitting diode LED, thereby reducing the triac (TAC). ) Is turned on, and thus the lamp LAMP is turned on.

At dawn when the bulb is turned on, the flip-flop 3 is triggered by the second pulse signal of the pulse generator 2 to bring the output terminal Q to a low level. Then, as the transistor TR1 is turned off, the triac TAC is turned off, and the light bulb LAMP is turned off. In this way, the lighting time of the light bulb LAMP is turned on a little early in the evening, as shown in FIG. 2 (e), and is turned off a little early so that the convenience of using the light bulb and power can be saved.

On the other hand, when the lamp LAMP is used over the prescribed value and the overcurrent flows, the current detected by the current transformer CT is rectified by the diode D1 and the capacitor C2 and supplied to the non-inverting terminal (+) of the comparator COMP1. When the over-current is supplied with a voltage higher than the reference voltage by the resistors R13 and R14, the output of the comparator COMP4 becomes a high level to set the flip-flop 6. Then, the output terminal Q becomes low level, which brings the connection point of the resistors R7 and R8 to the low level through the diode D2, thereby turning off the transistor TR1, thereby preventing the driving of the bulb LAMP. .

Therefore, when using a lamp of more than the rating (LAMP) it is possible to save the power consumption by turning off the lamp (LAMP) to be protected from overcurrent.

As described above, the present invention facilitates the use of a light bulb by turning it on or off a little early in the evening and early morning, and saves the power as much as turning off the light early in the morning. In addition to protecting the power consumption is effective.

Claims (4)

The photosensitive section 1 composed of the resistor R1 and the photoconductive element Cds1, the reference voltages of the variable resistors VR1, VR2 and R2-R5 and the photosensitive section 4 The output voltage of the pulse generator 2 outputs a pulse signal at the time of darkening and the time of lightening at the interconnected output terminals of the comparator COMP1 and COMP2, and the output signal of the pulse generator 2 A flip-flop 3 that is triggered and outputs a toggle signal accordingly, and a transistor TR1 and a resistor R7 that light the bulb LAMP through the triac TAC according to the output signal of the flip-flop 3. An overcurrent detector 5 composed of an R10, a diode D1, a capacitor C2, and a comparator COMP4, and an overcurrent detector 5 configured to detect an overcurrent of the overcurrent detector 5; A flip-flop (6) for turning off the operation, and a comparator (COMP3) and resistors (R16-R18) to reset the flip-flop (3) (6) in a bright state. Key is automatically lighting circuit, characterized in that consisting of the reset signal generator (7). The pulse generator 2 sets the reference voltage by the variable resistor VR1 higher than the reference voltage by the variable resistor VR2 to darken the signal of the pulse width according to the difference between the two reference voltages. Automatic lighting circuit, characterized in that for outputting when and when the light. 2. The flip-flop (3) according to claim 1, wherein the flip-flop (3) is triggered at the pulse initial time of the output pulses of the pulse generator (2) so as to light up early when the lamp (LAMP) is dim and bright through the triac driver (4). Automatic lighting circuit characterized in that it is to be turned off. 2. The flip-flop according to claim 1, wherein the reference voltage by the resistors R16 and R17 of the reset signal generator 7 is set lower than the reference voltage by the variable resistor VR2 of the comparator COMP2. (3) An automatic lighting circuit, characterized in that the lamp (LAMP) is turned off by setting (6).